Chair back frame



FIG. 1 is a perspective view of a chair back frame, showing my newdesign;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof; and,

FIG. 8 is a right side thereof mounted on a chair.

Wherein the broken lines are shown for illustrative purposes only andform no part of the claimed design.

CLAIM The ornamental design for a chair back frame, as shown anddescribed.